Originally, the magic was made for healers that can use water magic, so that they might be able to treat many people at once by engulfing them in a special kind of water produced by the spell. But Marie found a way to produce a similar effect to what was mentioned in the spell book. Although, the scale of her water was small to only cover from her wrists to her finger tips, it was good enough to heal a small injury as her dislocation.
The healing effect of this magic was supposed to be amplified when used, but Marie wasn't a healer, so she couldn't bring out the healing potential of the spell, just a little.
It might seem like it's nothing, but the fact that she could do something such as use even a little healing spell was a big achievement. After she returned to her room, she asked for nobody to disturb her no matter what until she came out, except the village was in danger.
